Most snowmobiles include a chassis, an engine, a transmission, and endless belt assembly designed to contact the ground and propel the snowmobile. Typical snowmobiles also include a pair of front skis support by a front suspension system. The endless belt assembly generally includes a rear suspension system designed to help the belt assembly maintain contact with the ground when riding over uneven terrain and provide the rider with a comfortable ride.
Generally, there are two types of snowmobile rear suspensions in the snowmobile industry: coupled and uncoupled. The term “coupled” is generally given to suspensions that have dependant kinematics front-to-rear and/or rear-to-front relative to the lower rails of the rear suspension. A suspension is coupled rear-to-front when the front portion of the lower rails is deflected vertically and the rear portion of the lower rails is forced to move vertically to some degree. A suspension is coupled rear-to-front when the rear portion of the lower rails is deflected vertically and the front portion of the lower rails is forced to move vertically to some degree. An uncoupled rear suspension is generally independent front-to-rear and rear-to-front relative to the lower rails of the rear suspension. A vertical deflection of the front portion of the suspension causes little to no vertical deflection of the rear portion of the suspension and vice versa.
Coupled suspensions differ from uncoupled suspension in at least two areas. There is a distinct stiffness or rate of deflection of the rear suspension per pound of force applied to the rear suspension for both the front and rear portion of the rear suspension. A coupled suspension combines the rates of both the front and rear portions of the rear suspension so the overall rate becomes higher than rate that may be achieved with an uncoupled rear suspension. Second, a coupled rear suspension may be used to control weight transfer to the rear suspension during acceleration of the snowmobile.
One embodiment of the present invention includes a snowmobile comprising a chassis, a motor supported by the chassis, and an endless belt assembly including a belt and a coupled suspension, the coupled suspension including a lower rail, a front and rear control arm, a first and second bump stop, and a coupling member positioned between the first and second bump stops, the front control arm adapted to operably connect the lower rail to the chassis, the rear control arm adapted to operably connect the coupling member to the chassis, the first bump stop supported by the lower rail at a first position, the second bump stop supported by the lower rail at a second position, the coupling member pivotally supported to the lower rail, the coupling member being moveable between the first bump stop and the second bump stop, the coupling member configured to exert a horizontal and vertical force on the second bump stop, the vertical force being greater than the horizontal force.
Another embodiment of the present invention includes a snowmobile having a coupled suspension, the snowmobile comprising a chassis having a front and rear end, a lower rail, a front control arm positioned adjacent to the chassis front end, the front control arm pivotally interconnecting the chassis and the lower rail, a rear inverted control link interconnected to the lower rail, a rear control arm positioned adjacent to the chassis rear end and pivotally interconnected to the chassis and the rear inverted control link, the rear control arm interconnected to the rear inverted control link at a position below the interconnection between the rear inverted control arm and the lower rail, and a coupling member providing a controlled degree of freedom of movement between the coupling member and the rear control arm, until coupling between the rear control arm and the lower rail occurs.
Another embodiment of the present invention includes a snowmobile comprising a chassis having a front and rear end, a lower rail, a front control arm defining a first length extending between first and second spaced-apart ends, the front control arm positioned adjacent to the chassis front end, the front control arm pivotally coupled to the chassis on the first end and pivotally coupled to the lower rail on the second end, a rear control arm positioned adjacent to the chassis rear end and pivotally interconnected to the chassis and lower rail, a linkage assembly supported by the front control arm at a first position between the first and second ends of the front control arm, the first position being spaced-apart from the second end of the front control arm by at least a first distance, the first distance being defined by one-quarter of the length of the front control arm, and a shock absorber and pull rod each including first and second spaced-apart ends, the first ends interconnected to the rear control arm, the second ends operably coupled to the linkage assembly.
Another embodiment of the present invention includes a snowmobile comprising a chassis having a front and rear end, a lower rail having front and rear ends, and an endless belt assembly including a belt, a front control arm, a rear control arm, a coupling member, and a belt tensioning system, the front control arm positioned adjacent to the chassis front end and adapted to pivotally interconnect the chassis and the lower rail, the rear control arm positioned adjacent to the chassis rear end and adapted to pivotally interconnect the chassis and one of the coupling member and the lower rail, the coupling member providing a controlled degree of freedom of movement between the coupling member and the rear control arm, the belt tensioning system configured to maintain an appropriate belt tension during movement between the chassis and lower rail.
In yet another embodiment, a snowmobile having a coupled suspension comprises a chassis, at least one lower rail, at least one front control arm pivotally coupled to the chassis at a first end and pivotally coupled to the lower rail on a second end, a rear control arm positioned adjacent to the chassis rear end and pivotally interconnected to the chassis and lower rail, a front linkage assembly supported by the front control arm, a rear linkage assembly supported by the rear control arm; a tension rod extending between the front and rear linkage, an LFE operatively connected between the front linkage assembly and the rear linkage assembly, and extending along a longitudinal line of action (LOA), where the LFE front pivot point and a front pivot point of the tension rod being substantially along the LOA, and being spaced apart from each other.
The above mentioned and other features of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings.
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention.